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Effect of Clipping Wings and Tails in Chicks
Effect of Clipping Wings and Tails in Chicks 1. COMPARATIVE DATA ON GROWTH, FEED INTAKE, FEATHERING AND MEAT QUALITY'-2 A. A. RASHEED AND J. E. OLDFIELD Department of Animal Science, and A. O. MACKEY Department of Home Economics Research, Oregon State University, Corvallis, Oregon
M
ANY studies have shown that tissues and organs develop at different rates in domestic animals from birth to maturity. This difference in rate of development has been associated with changes in proportions of the various tissues as the animal or bird matures. Palsson (1955) has reported results of many investigators which show that the development of organs and tissues is affected by nutrition. Also, Hammond (1944a) has explained the relationship between nutrition and the development of organs and tissues by his theory of "Partition of nutrients according to metabolic rate." In this connection, Palsson (1955) observed that Child (1920) was the first to show that tissues and organs with the highest metabolic rates had priority over those with lower metabolic rates for the supply of incoming nutrients No information is available, however, to illustrate the partition of incoming nutrients when parts of an organ or tissue are prevented from growth and development by surgical amputation, for example. Fowl would lend themselves particularly well to an investigation of this kind since appendages can be easily removed without affecting the birds' general health or activity. 1 Technical Paper No. 1638, Oregon Agricultural Experiment Station. 2 Supported by a grant from the Oregon Agricultural Experiment Station Administration.
Clipping parts of one or both wings is practiced with some domestic birds to prevent flight. This is carried out by either clipping off most of the flight feathers or removing the last segment of one or both wings. Marsden and Martin (1955) suggested cutting off the last segment from both wings at 7 days of age to prevent turkeys from flying. These workers added that this method facilitates feather plucking. Removal of the outer joint of the left wing had no effect on growth of turkeys up to 4 weeks of age according to Wyne et al. (1959). In the newly-hatched chick the wing is less-developed and is later maturing than the leg, and although wings form a significant part of a chicken they appear no longer to have an important physiological function (Palsson, 1955). Bradley (1960) believes that the effect of domestication and artificial selection was in the direction of discouraging flight. Yet the largest feathers in the fowl are those of the wings and tails (Bradley, 1960), and considerable diversion of nutrients must take place for their development. Feathers are also later-maturing than any of the bird's systems except the muscle and fat, according to Palsson (1955). Feather weight has been shown to be direiftly proportional to body weight; it also increases with the first power of body weight (Brody, 1945). Moreover, Latimer
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(Received for publication February 7, 1963)
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Because feathers are high in protein content (Naber, 1961) adequate dietary quantities of this nutrient as well as of specific amino acids are essential for the normal growth and development of birds. Bolton (1954) has indicated t h a t requirements of chicks for protein are greater in early life when growth is more rapid, and he agrees with others (Block and Weiss, 1956) t h a t very young fowl are required to divert large proportions of their dietary sulfur amino acids to the growth of feathers which are reported to contain 2 percent sulfur (Ewing, 1951). The literature reviewed does not indicate how much wing and tail feathers make up of the bird's total feather covering, however in turkeys, quill feathers made up 26.23 percent of total feathers according to H a m m o n d (1944b). Because of the size and structure of wing flight feathers and tail quill feathers it m a y be assumed t h a t a substantial quantity of dietary protein would be utilized in their formation. Possible competition among the various tissues and organs of the fowl for dietary protein has suggested the following study, carried out under conditions where certain wing and tail parts were surgically amputated to investigate: a) If there would be a change among remaining organs and tissues with regard to their uptake of nutrients, particularly those originally meant for the removed parts, if feed intake and composition re-
mains at a normal level, and b) if birds adjust their feed intake according to their actual needs under the imposed conditions. EXPERIMENTAL
Sixty eight day-old male chicks of the White VantressX Nichols 108 cross were used in this study. Preliminary investigations have shown t h a t surgical removal of the two distal parts from both wings at an early age did not jeopardize the survival of the chicks. T h e humeral part of the wing was not removed to avoid additional stress since the humerus bone cavity, connected with the clavicular air sac, is believed to play a part in the respiratory functions in the bird (Bradley, 1960). The chicks were randomly assigned to two groups of equal numbers. Each group was further subdivided into two groups of seventeen birds each. These subgroups were placed in four compartments of an electrically-heated starter battery to three weeks of age following which they were transferred to a finisher battery in rooms provided with 24-hour lights. The chicks were fed ad libitum a broiler ration shown in Table 1. Individual body weights were recorded for each bird at one day of age, at 14-days of age and at weekly intervals thereafter up to 8 weeks of age. Feed intake and efficiency of feed utilization (unit gain in weight/unit feed) was also recorded for each subgroup for the first two weeks of age and at weekly intervals thereafter. At three days of age, both wings in one group of chicks (group B) were clipped off at the joint between the humerus and the radius thereby removing the two distal segments of each thoracic limb bearing the flight feathers. Bleeding was prevented by tying a string tourniquet tightly around the end of the humerus. The string was removed after 24-hours to prevent fu-
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(1925) showed that body weight of Single Comb White Leghorns increased 70.3 times from hatching to maturity while feather weight increased 64.9 times in males and 48.1 times in females during the same period. In a later study, Latimer (1932) also showed t h a t feathers in newlyhatched male birds accounted for 3.7 percent of body weight while they accounted for 9.8 percent of body weight when birds weighed 1100 grams.
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WING AND TAIL CLIPPING
TABLE 1.—Composition of broiler ration fed to chicks during the entire period of study Component
Percent
Ground grain Animal fat 1 Soybean meal, dehulled (50% protein) Fish meal (70% protein) Meat and bone meal (50% protein) Alfalfa meal, dehydrated (20% protein) Limestone flour Salt, iodized Methionine hydroxy analogue (90%) Vitamin and mineral premix2 Coccidiostat3
64.75 4.65 15.35 5.80 5.90 2.00 0.80 0.30 0.15 0.25
+
1
Calogen (Swift & Co., Inc. Portland, Oregon), stabilized with Tenox R which is composed of 20% citric acid (anhydrous), 20% butylated hydroxyanisole and 60% propylene glycol. 2 Nopcosol M-5 (Nopco Chemical Co., Richmond, California), supplied/lb. of mixture: vit. A, 600,000 U.S.P.U.; vit. D 3 , 200,000 I.C.U.; vit. E, 200 I.U.; vit. K, 100 mg.; riboflavin, 600 mg.; d-pantothenic acid, 1 gm.; niacin, 4 gm.; choline, 40 gm.; vit. Bra, 1 mg.; Zn bacitracin, 800 mg.; butylated hydroxy toluene, 22.68 gm; Mn, 10.3 gm.; Fe, 3.6 gm.; Cu, 363 mg.; I, 218 mg.; Zn, 5 gm. ' Zoamix (Dow Chemical Co., Midland, Michigan), 227 mg./lb.
TABLE 2.—Average body weight, food intake and feed efficiency1 Intact Birds No. Average Body Weight: ' at8weeks at9weeks atlOweeks
34 20 10
Grams
1,563± 134.1** 1,831±184.1* 2,088±173.9*
Average Feed Intake: 8-weekperiod
2,926± 161.1**
Feed Efficiency: 8-weekperiod
.52 ±0.109
Grams
33 20 10
1,438±117.1 1,708± 141.9 1,913± 141.8
2,718±145.5 .51 ±0.088
1
Unit gain/unit feed. * Indicates significant difference at (P<0.05). ** Indicates significant difference at (P <0.01).
the ninth week and 20 each during the tenth and eleventh. Each batch of birds was killed within a period of 48 hours, and the following weights obtained: body at slaughter, blood lost during a 2-minute bleeding period, body feathers4 plus those only on the arms of both clipped and intact birds, the two distal segments of both wings on intact birds, the distal half of the tail region with attached feathers on intact birds, the full and emptied gizzard and crop, the edible parts of the viscera, and the dressed carcass. Dressed carcasses of the birds killed during the second interval and representing, in equal numbers, both treatment groups were washed in cold water, placed in plastic bags, sealed and quick frozen at -28.8°C. (-18°F.) for 24 hours. They were stored at - 18°C. (0°F.) for 4 weeks prior to their use to determine differences between treatment groups with respect to their white and dark meat qualities. The birds were roasted, uncovered, at 162.8°C. (325°F.) and were considered cooked when an internal temperature of 95°C. (203°F.) was reached in the breast muscle. Both evaporation and drip losses were determined. Tenderness, juiciness and flavor of breast and thigh meat samples were evaluated by a panel of 6 judges.
3
Purina "Chek-Pick", Ralston Purina Co., St. Louis 2, Missouri.
Clipped Birds No.
4
Feathers were dry-picked.
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ture damage to skin and muscle tissues around the humerus. At six days of age about half the coccygeal region bearing the quill feathers was clipped off using the same precautions as in the case of wings to prevent bleeding. Removing part of the tail was purposely delayed to reduce stress on chicks from surgery. An anti-pick3 ointment was applied on the cut surfaces after removing the strings from the sites of clipping. All experimental birds were debeaked at 8 days of age to reduce incidence of cannibalism especially among the clipped birds. One bird from the clipped group was lost when three weeks old. The feeding experiment terminated when the birds reached eight weeks of age. The birds were sacrificed at three separate weekly intervals because of limited slaughter facilities: 27 birds were killed during
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Intact Birds Clipped Birds
a M
1000
500
FIG. 1. Growth curves for intact and clipped birds
Data obtained were analyzed statistically according to a split-plot design (Snedecor, 1956). Dressed carcasses of birds killed during the third interval and also representing, in equal numbers, both treatment groups were placed in plastic bags without being washed. After sealing the bags, the birds were quick frozen and stored using similar temperatures as mentioned previously. Meat samples from this group were used for determining percentage dry matter, crude protein and ether extractable materials. Data other than for meat quality were subjected to statistical analysis using the method of analysis of variance and the ttest (Snedecor, 1956).
RESULTS
a) Growth Studies. Average body weight, feed intake and efficiency of feed utilization for the 8-week period are presented in Table 2. Growth curves of intact and clipped birds are shown in Figure 1. Table 2 also shows average body weight of birds remaining in each group by the end of the ninth and tenth weeks respectively. There was no difference in the average body weights of birds in the two groups at one day of age. At three days of age, average body weight of birds in group B prior to, and following the clipping of both wings was 51.6 and 49.5 grams, respectively. Average weight of the clipped-off parts of both wings was 2.07 + 0.42 grams which made up about 4.01 percent of the
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1500
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WING AND TAIL CLIPPING TABLE 3.—Slaughter data: comparisons between treatment groups using actual and adjusted body weights of control (intact) birds Sources of variation 1
1,830.3 + 1,688.1 + 123.2+ 19.0+ 1,182.2 +
244.2" 225.2 16.9 4.57 165.8
64.6+ 1.11 69.8+ 1.39 65.7+ 13.0 29.5+ 4.12 74.5+ 7.97 88.0+ 17.78
Clipped birds 1,705.1 + 246.1 1,705.1 + 246.1 1,192.7 + 184.3 69.9+ 69.9+ 63.3+ 28.3+ 72.3+
1.38** 1.38 8.1 3.87 8.16
98.91+ 18.52**
** Indicates significant difference at (P<0.01) 1 Weight based on empty crops and gizzards. 2 Weight obtained by removing at slaughter wings and tails at similar locations to those of birds in clipped group " B . " 3 Dressed carcass weight obtained after bleeding, dry-picking of feathers, evisceration, removal of head, legs and the two distal parts of both wings plus the distal part of the tail in intact birds. 4 Weight of blood lost during approximately 2 minute bleeding. 6 Combined weight of liver, spleen, heart and gizzard.
total body weight of the intact bird. As shown in Figure 1, the clipped birds were consistently lighter in weight than the intacts (P <0.01) up to 8 weeks of age. Birds remaining up till the tenth week of age also exhibited similar differences (P<0.05). The differences in mean body weights increased with age and averaged 38.5, 55.8, 57.3, 73.6, 86.2, 103.0, 124.7, 122.8 and 175.5 grams from the second to the tenth week, respectively. Intact birds consumed more feed than clipped ones up to 8 weeks of age (P <0.01) with larger differences observed during the first four weeks on trial. During the first two weeks, average feed intake of the intact bird exceeded that of the clipped one by 67.1 grams. Differences during the following weeks were 35.8, 37.4, 12.9, 14.3, 16.1 and 23.9 grams for the third to the eighth week, respectively, indicating an average excess in total feed intake of about 207.5 grams per intact bird. Clipped birds consumed about 7.1 percent less feed than their intact counterparts during the study period.
Numerical differences were obtained between both treatment groups with respect to feed utilization but they lacked statistical significance. b) Slaughter Studies. Data collected at slaughter are presented in Table 3. Live weights of intact birds, were significantly higher than those of clipped ones (P<0.01). When body weights were compared after removal of both wings (at the joint between the humerus bone and the radius) and the distal half of the tail from intact birds no significant differences were demonstrated between both groups of birds. Results also indicate that the excess in body weight of intact birds above that of clipped ones is mainly due to the presence of the fore-arm and manus parts of the wings as well as the distal part of the tail with their feather complements. No differences were obtained between dressed weights of intact and clipped birds. Clipped birds showed a significantly higher dressing percentage than intacts (P<0.01). However, when comparisons were made on the basis of the ad-
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Corrected live weight, gm. Adjusted body weight,2 intacts, gm. Weight of wings, intacts, gm. Weight of tails, 3intacts, gm. Dressed weight, gm. Percent dressed weight: using actual weight of intacts using adjusted weight of intacts Blood weight,4 gm. Liver weight, gm. Edible viscera,6 gm. Weight of feathers on body proper, legs and arm portion of wings, gm.
Intact birds
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MACKEY
d) Composition of Breast Muscle. D a t a concerning percent dry matter, percent crude protein and percent ether extract of breast meat samples are presented in Table 4. Results indicate no differences in composition of breast meat for these constituents from the two t r e a t m e n t groups.
c) Cooking Results and Meat Quality Scores. Evaporation and drip losses during cooking are presented in Table 4. There were no significant differences between t r e a t m e n t groups. D a t a regarding scores for tenderness,
DISCUSSION
Growth and development of most tissues and organs of chicks were not
TABLE 4.—Average values for cooking losses, meat quality scores and chemical composition of breast muscle Intact Birds
Clipped Birds
Cooking losses: Thawed, uncooked birds, gm. Evaporation loss, percent Drip loss, percent
1,201 + 141.89 13.5 + 2.91 8.9 + 1.92
Meat quality scores: Tenderness: breast meat samples thigh meat samples combined samples
19.5 28.2
+ +
5.87 2.86 23.9 + 6.33
35.2 + 32.3 +
1,238+120.06 13.2 + 2.31 9.8 + 1.42 3.73** 3.92** 33.8 + 4.01**
Juiciness:
breast meat samples thigh meat samples combined samples
22.9 26.1
+ +
2.96 0.95 25.6 + 3.50
28.3 + 29.1 +
2.92 3.17 27.6 + 3.34**
Flavor:
breast meat samples thigh meat samples combined samples
23.7 23.1
+ +
2.71 2.23 23.4 + 2.44
25.7 ± 24.2 +
1.49 2.53 25.0+4.68
Breast muscle composition: Dry matter, percent Crude protein, percent Ether extract, percent
25.89± 87.75 + 1.86 +
0.29 1.12 0.44
26.05+ 88.30+ 1.98+
0.42 1.75 0.25
Meat quality scores were based on a scale of 1 to 7; a score of 7 indicating the highest degree of desirability of each of the quality attributes. Each of the above values represents the combined scores of six judges averaged for 10 birds. ** Indicates significant difference at (P<0.01).
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juiciness and flavor of both breast and thigh meat samples are presented in Table 4. Results indicate t h a t both white and dark meat from clipped birds were more tender than those from intact birds ( P < 0 . 0 1 ) , more so between breast meat samples than those from thigh meat. Statistical analysis also showed t h a t both kinds of meat from clipped birds were more juicy than those from intacts ( P < 0 . 0 1 ) . No differences were obtained between groups with respect to flavor.
justed body weights of intact birds no differences in dressing percentages were shown. There were no differences between intact and clipped birds with respect to (a) amount of blood lost, (b) blood hemoglobin (8.85 and 8.92 gm./lOO ml. for intacts and clipped, respectively), (c) blood hematocrit (29.5 percent for both groups), (d) absolute liver weight, and (e) weight of edible viscera. Hemoglobin and hematocrit values of 9.7 gm./lOO ml. and 29 percent respectively, have been reported for male chicks of similar ages (Sturkie, 1954). Feather covering of clipped birds was significantly heavier than on corresponding body areas of intacts ( P < 0 . 0 1 ) , irrespective of interval.
W I N G AND T A I L C L I P P I N G
Judging from the fact that no differences were shown between the two groups with respect to certain organ and tissue weights (Table 3) it appears that no major alterations in the differential rate of tissue growth and development occurred as a result of wing and tail clipping. This would support the view that most tissues and organs in the clipped group showed no priority among themselves for utilizing nutrients originally meant for the missing wing and tail parts. Increased feathering in the clipped group, however, may have resulted from the diversion to this system of some nutrients, particularly proteins, originally intended for wing and tail feather formation. This probably demonstrates priority of the feather system over others for nutrients available in excess of quantities needed for normal body growth and development of chicks. The possibility exists t h a t clipped birds may have compensated for their lack of wings by increased feathering to maintain body temperature (Plates 1 and 2).
PLATE 1. Clipped bird 6 weeks old
Increased feathering could be explained also on the basis of an induced hyperthyroid condition arising from the surgical reduction in the body weight of clipped birds amounting to approximately 7.8 percent of normal with no simultaneous reduction in thyroid size. This would increase the ratio of thyroid tissue per unit body weight. Various investigators have reported increased feathering in chicks fed iodinated casein (Boone et al., 1950; Glazener et al, 1949; Irwin et al., 1943; Turner et al., 1944) who also showed t h a t improved feathering was not necessarily associated with overall growth stimulation. Of particular interest in this study are results obtained between treatment groups with respect to meat quality. Both breast and thigh meat samples from clipped birds were significantly tenderer and juicier than those from intacts. Panel scores showed t h a t these differences were especially pronounced between breast meat samples. As a direct result of the
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affected, under conditions of this experiment, by removal during the first week of age of wing and tail parts bearing flight and quill feathers. Live weights of clipped birds differed from those of intacts in amounts corresponding to the sum weights of the wing and tail parts missing in the former group. The combined weight of wing and tail parts of intact birds which correspond to those removed from clipped birds make up about 7.8 percent of the body weight of the former group. Feed intake was reduced by about 7 percent for the clipped birds as compared to the control, probably because of the lower growth requirements in the clipped group. This reduction in feed intake represents a substantial saving of some essential nutrients which, otherwise would have been utilized in the formation of tissues of little value to producer, consumer or the bird itself in its modern habitat.
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A. A. R A S H E E D , J. E. OLDFIELD AND A. 0 .
expected lowered activity arising from the reduction in the size and weight of the wing organ the increased tenderness of breast muscles from clipped birds had been anticipated. I t had also been anticipated that in conjunction with the reduced activity of breast muscles increased deposition of fat would take place, leading to juicier breast meat. Improved juiciness did take place among the clipped birds but chemical analysis did not support the supposition that this was due to increased fat deposition. Similarity in the composition of breast meat may explain in part lack of differences in the flavor of meat from both groups. The possibility exists t h a t differences in the physiological activity of muscles leading to such significant differences in muscle characteristics may have occurred as a result of clipping. SUMMARY
1. Thirty four day-old chicks of the White VantressX Nichols 108 cross had
the two distal segments of both wings and the distal half of the tails clipped off during the first eight days of age. An equal number of birds served as a control. The birds were fed ad libitum and feed intake recorded to eight weeks of age. 2. I n t a c t birds were consistently heavier and consumed 7.1 percent more feed than the clipped birds during the period of study. There were no differences with respect to efficiency of feed utilization. 3. Birds from both groups were killed at three intervals during which time it was shown t h a t no differences existed with respect to dressed weight, blood lost during bleeding, liver weight and the weight of edible viscera. Similar blood hemoglobin and hematocrit values were obtained from both groups. On the other hand, clipped birds showed heavier plumage than those of corresponding areas of intacts. Clipped birds also dressed higher than intacts, however when comparisons were calculated on an adjusted weight basis for the intacts, no differences were shown. 4. Meat from clipped birds was more tender and juicy than t h a t from intacts, however the flavor did not differ between the two groups. The difference in tenderness and juiciness was not due to a difference in muscle composition since dry m a t t e r content of breast muscle as well as crude protein and ether extract did not differ between both groups. ACKNOWLEDGEMENT
Special gratitude is tendered Dr. G. H. Arscott, for his advice and assistance and to the Dept. of Poultry Science for providing facilities used in carrying out this experiment. REFERENCES Block, R. J., and K. W. Weiss, 1956. Amino Acid Handbook. Charles C Thomas, Illinois. Bolton, W\, 1954. Poultry, 106-143. In Hammond,
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PLATE 2. Intact bird 6 weeks old
MACKEY
W I N G AND T A I L C L I P P I N G
J. (editor) Progress in the Physiology of Farm Animals, Butterworths Scientific Publications, London. Boone, M. A., J. A. Davidson and E. P. Reineke, 1950. Thyroid studies in fast and slow-feathering Rhode Island Red chicks. Poultry Sci. 29:195200. Bradley, 0 . C , 1960. The Structure of the Fowl. Oliver and Boyd, Edinburgh, London. Brody, S., 1945. Bioenergetics and Growth. Reinhold Publishing Corp., New York. Ewing, W. R., 1951. Poultry Nutrition, 4th Ed., Revised. W. R. Ewing Publisher, South Pasadena, California. Glazener, E. W., C. S. Shaffner and M. A. Jull, 1949. Thyroid activity as related to strain differences in growing chickens. Poultry Sci. 28:834-849. Hammond, J., 1944a. Physiological factors affecting birth weight. Proc. Nutr. Soc. 2:8-12. Hammond, J. C , 1944b. Feather yields in turkeys. Poultry Sci. 23:247. Irwin, M. R., E. P. Reineke and C. W. Turner, 1943. Effect of feeding thyroactive iodocasein on growth, feathering and weights of glands of young chicks. Poultry Sci. 22:374-380. Latimer, H. B., 1925. The relative postnatal growth of the systems and organs of the chicken. Anat. Record, 31:233-253. Latimer, H. B., 1932. Postnatal growth changes in the Single Comb White Leghorn chicken. Univ. Kansas Sci. Bull. 20(9): 199-206.
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Marsden, S. J., and J. H. Martin, 1955. Turkey Management, 6th Ed., The Interstate, Danville, Illinois. Naber, E. C , 1961. Utilization of poultry byproducts in feeds, 22-40. In Processing of poultry byproducts and their utilization in feeds. U.S.D.A. Utilization Research Report No. 3. Palsson, H., 1955. Conformation and body composition, 430-542. In Hammond, J. (editor) Progress in the Physiology of Farm Animals, Butterworths Scientific Publications, London.
Turner, C. W., M. R. Irwin and E. P. Reineke, 1944. Effect of feeding thyroactive iodocasein to Barred Rock cockerels. Poultry Sci. 23:242-246. Wheeler, R. S., E. Hoffmann and C. L. Graham, 1948. The value of thyroprotein in starting, growing and laying rations. 1. Growth, feathering and feed consumption of Rhode Island Red broilers. Poultry Sci. 27:103-111. Wyne, J. W., M. G. McCartney, R. D. Carter and V. D. Chamberlin, 1959. The effect of debeaking and wing clipping on growth and livability of turkey poults. Poultry Sci. 38:831-833.
Bone Darkening in Fryer Chickens as Related to Calcium and Phosphorus Levels in the Feed A N T H O N Y W. K O T U L A , J A M E S E . T H O M S O N AND J A M E S F . NOVOTNY
Market Quality Research Division, Agricultural Marketing Service, and E D M U N D H. M C N A L L Y
Animal Husbandry Research Division, Agricultural Research Service, United States Department of Agriculture, Beltsville, Maryland (Received for publication December 26, 1962)
T
fryer
it develops. Bone and meat discoloration
chickens is a fast growing enterprise
t h a t occurs during cooking of fryer chick-
in the poultry i n d u s t r y . T h e sooner the
ens which have been frozen m a y contrib-
actual
ute to the a p p a r e n t l y low consumer ac-
HE
or
associated
freezing
of
potential with
eviscerated
technical
freezing
problems
chickens
are
ceptability of these products.
solved, the better prepared the i n d u s t r y
Koonz (1946) indicated t h a t the mecha-
will be to meet the expanding d e m a n d , as
nism of darkening involves the leaching of
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Snedecor, G. W., 1956. Statistical Methods, 5th Ed., The Iowa State University Press, Ames, Iowa. Sturkie, P. D., 1954. Avian Physiology. Comstock Publishing Associates, Ithaca, N.Y. Titus, H. W., 1961. The Scientific Feeding of Chickens, 4th Ed., The Interstate, Danville, Illinois.
M
ANY studies have shown that tissues and organs develop at different rates in domestic animals from birth to maturity. This difference in rate of development has been associated with changes in proportions of the various tissues as the animal or bird matures. Palsson (1955) has reported results of many investigators which show that the development of organs and tissues is affected by nutrition. Also, Hammond (1944a) has explained the relationship between nutrition and the development of organs and tissues by his theory of "Partition of nutrients according to metabolic rate." In this connection, Palsson (1955) observed that Child (1920) was the first to show that tissues and organs with the highest metabolic rates had priority over those with lower metabolic rates for the supply of incoming nutrients No information is available, however, to illustrate the partition of incoming nutrients when parts of an organ or tissue are prevented from growth and development by surgical amputation, for example. Fowl would lend themselves particularly well to an investigation of this kind since appendages can be easily removed without affecting the birds' general health or activity. 1 Technical Paper No. 1638, Oregon Agricultural Experiment Station. 2 Supported by a grant from the Oregon Agricultural Experiment Station Administration.
Clipping parts of one or both wings is practiced with some domestic birds to prevent flight. This is carried out by either clipping off most of the flight feathers or removing the last segment of one or both wings. Marsden and Martin (1955) suggested cutting off the last segment from both wings at 7 days of age to prevent turkeys from flying. These workers added that this method facilitates feather plucking. Removal of the outer joint of the left wing had no effect on growth of turkeys up to 4 weeks of age according to Wyne et al. (1959). In the newly-hatched chick the wing is less-developed and is later maturing than the leg, and although wings form a significant part of a chicken they appear no longer to have an important physiological function (Palsson, 1955). Bradley (1960) believes that the effect of domestication and artificial selection was in the direction of discouraging flight. Yet the largest feathers in the fowl are those of the wings and tails (Bradley, 1960), and considerable diversion of nutrients must take place for their development. Feathers are also later-maturing than any of the bird's systems except the muscle and fat, according to Palsson (1955). Feather weight has been shown to be direiftly proportional to body weight; it also increases with the first power of body weight (Brody, 1945). Moreover, Latimer
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(Received for publication February 7, 1963)
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Because feathers are high in protein content (Naber, 1961) adequate dietary quantities of this nutrient as well as of specific amino acids are essential for the normal growth and development of birds. Bolton (1954) has indicated t h a t requirements of chicks for protein are greater in early life when growth is more rapid, and he agrees with others (Block and Weiss, 1956) t h a t very young fowl are required to divert large proportions of their dietary sulfur amino acids to the growth of feathers which are reported to contain 2 percent sulfur (Ewing, 1951). The literature reviewed does not indicate how much wing and tail feathers make up of the bird's total feather covering, however in turkeys, quill feathers made up 26.23 percent of total feathers according to H a m m o n d (1944b). Because of the size and structure of wing flight feathers and tail quill feathers it m a y be assumed t h a t a substantial quantity of dietary protein would be utilized in their formation. Possible competition among the various tissues and organs of the fowl for dietary protein has suggested the following study, carried out under conditions where certain wing and tail parts were surgically amputated to investigate: a) If there would be a change among remaining organs and tissues with regard to their uptake of nutrients, particularly those originally meant for the removed parts, if feed intake and composition re-
mains at a normal level, and b) if birds adjust their feed intake according to their actual needs under the imposed conditions. EXPERIMENTAL
Sixty eight day-old male chicks of the White VantressX Nichols 108 cross were used in this study. Preliminary investigations have shown t h a t surgical removal of the two distal parts from both wings at an early age did not jeopardize the survival of the chicks. T h e humeral part of the wing was not removed to avoid additional stress since the humerus bone cavity, connected with the clavicular air sac, is believed to play a part in the respiratory functions in the bird (Bradley, 1960). The chicks were randomly assigned to two groups of equal numbers. Each group was further subdivided into two groups of seventeen birds each. These subgroups were placed in four compartments of an electrically-heated starter battery to three weeks of age following which they were transferred to a finisher battery in rooms provided with 24-hour lights. The chicks were fed ad libitum a broiler ration shown in Table 1. Individual body weights were recorded for each bird at one day of age, at 14-days of age and at weekly intervals thereafter up to 8 weeks of age. Feed intake and efficiency of feed utilization (unit gain in weight/unit feed) was also recorded for each subgroup for the first two weeks of age and at weekly intervals thereafter. At three days of age, both wings in one group of chicks (group B) were clipped off at the joint between the humerus and the radius thereby removing the two distal segments of each thoracic limb bearing the flight feathers. Bleeding was prevented by tying a string tourniquet tightly around the end of the humerus. The string was removed after 24-hours to prevent fu-
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(1925) showed that body weight of Single Comb White Leghorns increased 70.3 times from hatching to maturity while feather weight increased 64.9 times in males and 48.1 times in females during the same period. In a later study, Latimer (1932) also showed t h a t feathers in newlyhatched male birds accounted for 3.7 percent of body weight while they accounted for 9.8 percent of body weight when birds weighed 1100 grams.
1003
WING AND TAIL CLIPPING
TABLE 1.—Composition of broiler ration fed to chicks during the entire period of study Component
Percent
Ground grain Animal fat 1 Soybean meal, dehulled (50% protein) Fish meal (70% protein) Meat and bone meal (50% protein) Alfalfa meal, dehydrated (20% protein) Limestone flour Salt, iodized Methionine hydroxy analogue (90%) Vitamin and mineral premix2 Coccidiostat3
64.75 4.65 15.35 5.80 5.90 2.00 0.80 0.30 0.15 0.25
+
1
Calogen (Swift & Co., Inc. Portland, Oregon), stabilized with Tenox R which is composed of 20% citric acid (anhydrous), 20% butylated hydroxyanisole and 60% propylene glycol. 2 Nopcosol M-5 (Nopco Chemical Co., Richmond, California), supplied/lb. of mixture: vit. A, 600,000 U.S.P.U.; vit. D 3 , 200,000 I.C.U.; vit. E, 200 I.U.; vit. K, 100 mg.; riboflavin, 600 mg.; d-pantothenic acid, 1 gm.; niacin, 4 gm.; choline, 40 gm.; vit. Bra, 1 mg.; Zn bacitracin, 800 mg.; butylated hydroxy toluene, 22.68 gm; Mn, 10.3 gm.; Fe, 3.6 gm.; Cu, 363 mg.; I, 218 mg.; Zn, 5 gm. ' Zoamix (Dow Chemical Co., Midland, Michigan), 227 mg./lb.
TABLE 2.—Average body weight, food intake and feed efficiency1 Intact Birds No. Average Body Weight: ' at8weeks at9weeks atlOweeks
34 20 10
Grams
1,563± 134.1** 1,831±184.1* 2,088±173.9*
Average Feed Intake: 8-weekperiod
2,926± 161.1**
Feed Efficiency: 8-weekperiod
.52 ±0.109
Grams
33 20 10
1,438±117.1 1,708± 141.9 1,913± 141.8
2,718±145.5 .51 ±0.088
1
Unit gain/unit feed. * Indicates significant difference at (P<0.05). ** Indicates significant difference at (P <0.01).
the ninth week and 20 each during the tenth and eleventh. Each batch of birds was killed within a period of 48 hours, and the following weights obtained: body at slaughter, blood lost during a 2-minute bleeding period, body feathers4 plus those only on the arms of both clipped and intact birds, the two distal segments of both wings on intact birds, the distal half of the tail region with attached feathers on intact birds, the full and emptied gizzard and crop, the edible parts of the viscera, and the dressed carcass. Dressed carcasses of the birds killed during the second interval and representing, in equal numbers, both treatment groups were washed in cold water, placed in plastic bags, sealed and quick frozen at -28.8°C. (-18°F.) for 24 hours. They were stored at - 18°C. (0°F.) for 4 weeks prior to their use to determine differences between treatment groups with respect to their white and dark meat qualities. The birds were roasted, uncovered, at 162.8°C. (325°F.) and were considered cooked when an internal temperature of 95°C. (203°F.) was reached in the breast muscle. Both evaporation and drip losses were determined. Tenderness, juiciness and flavor of breast and thigh meat samples were evaluated by a panel of 6 judges.
3
Purina "Chek-Pick", Ralston Purina Co., St. Louis 2, Missouri.
Clipped Birds No.
4
Feathers were dry-picked.
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ture damage to skin and muscle tissues around the humerus. At six days of age about half the coccygeal region bearing the quill feathers was clipped off using the same precautions as in the case of wings to prevent bleeding. Removing part of the tail was purposely delayed to reduce stress on chicks from surgery. An anti-pick3 ointment was applied on the cut surfaces after removing the strings from the sites of clipping. All experimental birds were debeaked at 8 days of age to reduce incidence of cannibalism especially among the clipped birds. One bird from the clipped group was lost when three weeks old. The feeding experiment terminated when the birds reached eight weeks of age. The birds were sacrificed at three separate weekly intervals because of limited slaughter facilities: 27 birds were killed during
1004
A. A. RASHEED, J. E. OLDFIELD AND A. O. MACKEY
2000
Intact Birds Clipped Birds
a M
1000
500
FIG. 1. Growth curves for intact and clipped birds
Data obtained were analyzed statistically according to a split-plot design (Snedecor, 1956). Dressed carcasses of birds killed during the third interval and also representing, in equal numbers, both treatment groups were placed in plastic bags without being washed. After sealing the bags, the birds were quick frozen and stored using similar temperatures as mentioned previously. Meat samples from this group were used for determining percentage dry matter, crude protein and ether extractable materials. Data other than for meat quality were subjected to statistical analysis using the method of analysis of variance and the ttest (Snedecor, 1956).
RESULTS
a) Growth Studies. Average body weight, feed intake and efficiency of feed utilization for the 8-week period are presented in Table 2. Growth curves of intact and clipped birds are shown in Figure 1. Table 2 also shows average body weight of birds remaining in each group by the end of the ninth and tenth weeks respectively. There was no difference in the average body weights of birds in the two groups at one day of age. At three days of age, average body weight of birds in group B prior to, and following the clipping of both wings was 51.6 and 49.5 grams, respectively. Average weight of the clipped-off parts of both wings was 2.07 + 0.42 grams which made up about 4.01 percent of the
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1500
1005
WING AND TAIL CLIPPING TABLE 3.—Slaughter data: comparisons between treatment groups using actual and adjusted body weights of control (intact) birds Sources of variation 1
1,830.3 + 1,688.1 + 123.2+ 19.0+ 1,182.2 +
244.2" 225.2 16.9 4.57 165.8
64.6+ 1.11 69.8+ 1.39 65.7+ 13.0 29.5+ 4.12 74.5+ 7.97 88.0+ 17.78
Clipped birds 1,705.1 + 246.1 1,705.1 + 246.1 1,192.7 + 184.3 69.9+ 69.9+ 63.3+ 28.3+ 72.3+
1.38** 1.38 8.1 3.87 8.16
98.91+ 18.52**
** Indicates significant difference at (P<0.01) 1 Weight based on empty crops and gizzards. 2 Weight obtained by removing at slaughter wings and tails at similar locations to those of birds in clipped group " B . " 3 Dressed carcass weight obtained after bleeding, dry-picking of feathers, evisceration, removal of head, legs and the two distal parts of both wings plus the distal part of the tail in intact birds. 4 Weight of blood lost during approximately 2 minute bleeding. 6 Combined weight of liver, spleen, heart and gizzard.
total body weight of the intact bird. As shown in Figure 1, the clipped birds were consistently lighter in weight than the intacts (P <0.01) up to 8 weeks of age. Birds remaining up till the tenth week of age also exhibited similar differences (P<0.05). The differences in mean body weights increased with age and averaged 38.5, 55.8, 57.3, 73.6, 86.2, 103.0, 124.7, 122.8 and 175.5 grams from the second to the tenth week, respectively. Intact birds consumed more feed than clipped ones up to 8 weeks of age (P <0.01) with larger differences observed during the first four weeks on trial. During the first two weeks, average feed intake of the intact bird exceeded that of the clipped one by 67.1 grams. Differences during the following weeks were 35.8, 37.4, 12.9, 14.3, 16.1 and 23.9 grams for the third to the eighth week, respectively, indicating an average excess in total feed intake of about 207.5 grams per intact bird. Clipped birds consumed about 7.1 percent less feed than their intact counterparts during the study period.
Numerical differences were obtained between both treatment groups with respect to feed utilization but they lacked statistical significance. b) Slaughter Studies. Data collected at slaughter are presented in Table 3. Live weights of intact birds, were significantly higher than those of clipped ones (P<0.01). When body weights were compared after removal of both wings (at the joint between the humerus bone and the radius) and the distal half of the tail from intact birds no significant differences were demonstrated between both groups of birds. Results also indicate that the excess in body weight of intact birds above that of clipped ones is mainly due to the presence of the fore-arm and manus parts of the wings as well as the distal part of the tail with their feather complements. No differences were obtained between dressed weights of intact and clipped birds. Clipped birds showed a significantly higher dressing percentage than intacts (P<0.01). However, when comparisons were made on the basis of the ad-
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Corrected live weight, gm. Adjusted body weight,2 intacts, gm. Weight of wings, intacts, gm. Weight of tails, 3intacts, gm. Dressed weight, gm. Percent dressed weight: using actual weight of intacts using adjusted weight of intacts Blood weight,4 gm. Liver weight, gm. Edible viscera,6 gm. Weight of feathers on body proper, legs and arm portion of wings, gm.
Intact birds
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A. A. R A S H E E D , J. E. O L D F I E L D AND A. 0 .
MACKEY
d) Composition of Breast Muscle. D a t a concerning percent dry matter, percent crude protein and percent ether extract of breast meat samples are presented in Table 4. Results indicate no differences in composition of breast meat for these constituents from the two t r e a t m e n t groups.
c) Cooking Results and Meat Quality Scores. Evaporation and drip losses during cooking are presented in Table 4. There were no significant differences between t r e a t m e n t groups. D a t a regarding scores for tenderness,
DISCUSSION
Growth and development of most tissues and organs of chicks were not
TABLE 4.—Average values for cooking losses, meat quality scores and chemical composition of breast muscle Intact Birds
Clipped Birds
Cooking losses: Thawed, uncooked birds, gm. Evaporation loss, percent Drip loss, percent
1,201 + 141.89 13.5 + 2.91 8.9 + 1.92
Meat quality scores: Tenderness: breast meat samples thigh meat samples combined samples
19.5 28.2
+ +
5.87 2.86 23.9 + 6.33
35.2 + 32.3 +
1,238+120.06 13.2 + 2.31 9.8 + 1.42 3.73** 3.92** 33.8 + 4.01**
Juiciness:
breast meat samples thigh meat samples combined samples
22.9 26.1
+ +
2.96 0.95 25.6 + 3.50
28.3 + 29.1 +
2.92 3.17 27.6 + 3.34**
Flavor:
breast meat samples thigh meat samples combined samples
23.7 23.1
+ +
2.71 2.23 23.4 + 2.44
25.7 ± 24.2 +
1.49 2.53 25.0+4.68
Breast muscle composition: Dry matter, percent Crude protein, percent Ether extract, percent
25.89± 87.75 + 1.86 +
0.29 1.12 0.44
26.05+ 88.30+ 1.98+
0.42 1.75 0.25
Meat quality scores were based on a scale of 1 to 7; a score of 7 indicating the highest degree of desirability of each of the quality attributes. Each of the above values represents the combined scores of six judges averaged for 10 birds. ** Indicates significant difference at (P<0.01).
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juiciness and flavor of both breast and thigh meat samples are presented in Table 4. Results indicate t h a t both white and dark meat from clipped birds were more tender than those from intact birds ( P < 0 . 0 1 ) , more so between breast meat samples than those from thigh meat. Statistical analysis also showed t h a t both kinds of meat from clipped birds were more juicy than those from intacts ( P < 0 . 0 1 ) . No differences were obtained between groups with respect to flavor.
justed body weights of intact birds no differences in dressing percentages were shown. There were no differences between intact and clipped birds with respect to (a) amount of blood lost, (b) blood hemoglobin (8.85 and 8.92 gm./lOO ml. for intacts and clipped, respectively), (c) blood hematocrit (29.5 percent for both groups), (d) absolute liver weight, and (e) weight of edible viscera. Hemoglobin and hematocrit values of 9.7 gm./lOO ml. and 29 percent respectively, have been reported for male chicks of similar ages (Sturkie, 1954). Feather covering of clipped birds was significantly heavier than on corresponding body areas of intacts ( P < 0 . 0 1 ) , irrespective of interval.
W I N G AND T A I L C L I P P I N G
Judging from the fact that no differences were shown between the two groups with respect to certain organ and tissue weights (Table 3) it appears that no major alterations in the differential rate of tissue growth and development occurred as a result of wing and tail clipping. This would support the view that most tissues and organs in the clipped group showed no priority among themselves for utilizing nutrients originally meant for the missing wing and tail parts. Increased feathering in the clipped group, however, may have resulted from the diversion to this system of some nutrients, particularly proteins, originally intended for wing and tail feather formation. This probably demonstrates priority of the feather system over others for nutrients available in excess of quantities needed for normal body growth and development of chicks. The possibility exists t h a t clipped birds may have compensated for their lack of wings by increased feathering to maintain body temperature (Plates 1 and 2).
PLATE 1. Clipped bird 6 weeks old
Increased feathering could be explained also on the basis of an induced hyperthyroid condition arising from the surgical reduction in the body weight of clipped birds amounting to approximately 7.8 percent of normal with no simultaneous reduction in thyroid size. This would increase the ratio of thyroid tissue per unit body weight. Various investigators have reported increased feathering in chicks fed iodinated casein (Boone et al., 1950; Glazener et al, 1949; Irwin et al., 1943; Turner et al., 1944) who also showed t h a t improved feathering was not necessarily associated with overall growth stimulation. Of particular interest in this study are results obtained between treatment groups with respect to meat quality. Both breast and thigh meat samples from clipped birds were significantly tenderer and juicier than those from intacts. Panel scores showed t h a t these differences were especially pronounced between breast meat samples. As a direct result of the
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affected, under conditions of this experiment, by removal during the first week of age of wing and tail parts bearing flight and quill feathers. Live weights of clipped birds differed from those of intacts in amounts corresponding to the sum weights of the wing and tail parts missing in the former group. The combined weight of wing and tail parts of intact birds which correspond to those removed from clipped birds make up about 7.8 percent of the body weight of the former group. Feed intake was reduced by about 7 percent for the clipped birds as compared to the control, probably because of the lower growth requirements in the clipped group. This reduction in feed intake represents a substantial saving of some essential nutrients which, otherwise would have been utilized in the formation of tissues of little value to producer, consumer or the bird itself in its modern habitat.
1007
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A. A. R A S H E E D , J. E. OLDFIELD AND A. 0 .
expected lowered activity arising from the reduction in the size and weight of the wing organ the increased tenderness of breast muscles from clipped birds had been anticipated. I t had also been anticipated that in conjunction with the reduced activity of breast muscles increased deposition of fat would take place, leading to juicier breast meat. Improved juiciness did take place among the clipped birds but chemical analysis did not support the supposition that this was due to increased fat deposition. Similarity in the composition of breast meat may explain in part lack of differences in the flavor of meat from both groups. The possibility exists t h a t differences in the physiological activity of muscles leading to such significant differences in muscle characteristics may have occurred as a result of clipping. SUMMARY
1. Thirty four day-old chicks of the White VantressX Nichols 108 cross had
the two distal segments of both wings and the distal half of the tails clipped off during the first eight days of age. An equal number of birds served as a control. The birds were fed ad libitum and feed intake recorded to eight weeks of age. 2. I n t a c t birds were consistently heavier and consumed 7.1 percent more feed than the clipped birds during the period of study. There were no differences with respect to efficiency of feed utilization. 3. Birds from both groups were killed at three intervals during which time it was shown t h a t no differences existed with respect to dressed weight, blood lost during bleeding, liver weight and the weight of edible viscera. Similar blood hemoglobin and hematocrit values were obtained from both groups. On the other hand, clipped birds showed heavier plumage than those of corresponding areas of intacts. Clipped birds also dressed higher than intacts, however when comparisons were calculated on an adjusted weight basis for the intacts, no differences were shown. 4. Meat from clipped birds was more tender and juicy than t h a t from intacts, however the flavor did not differ between the two groups. The difference in tenderness and juiciness was not due to a difference in muscle composition since dry m a t t e r content of breast muscle as well as crude protein and ether extract did not differ between both groups. ACKNOWLEDGEMENT
Special gratitude is tendered Dr. G. H. Arscott, for his advice and assistance and to the Dept. of Poultry Science for providing facilities used in carrying out this experiment. REFERENCES Block, R. J., and K. W. Weiss, 1956. Amino Acid Handbook. Charles C Thomas, Illinois. Bolton, W\, 1954. Poultry, 106-143. In Hammond,
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PLATE 2. Intact bird 6 weeks old
MACKEY
W I N G AND T A I L C L I P P I N G
J. (editor) Progress in the Physiology of Farm Animals, Butterworths Scientific Publications, London. Boone, M. A., J. A. Davidson and E. P. Reineke, 1950. Thyroid studies in fast and slow-feathering Rhode Island Red chicks. Poultry Sci. 29:195200. Bradley, 0 . C , 1960. The Structure of the Fowl. Oliver and Boyd, Edinburgh, London. Brody, S., 1945. Bioenergetics and Growth. Reinhold Publishing Corp., New York. Ewing, W. R., 1951. Poultry Nutrition, 4th Ed., Revised. W. R. Ewing Publisher, South Pasadena, California. Glazener, E. W., C. S. Shaffner and M. A. Jull, 1949. Thyroid activity as related to strain differences in growing chickens. Poultry Sci. 28:834-849. Hammond, J., 1944a. Physiological factors affecting birth weight. Proc. Nutr. Soc. 2:8-12. Hammond, J. C , 1944b. Feather yields in turkeys. Poultry Sci. 23:247. Irwin, M. R., E. P. Reineke and C. W. Turner, 1943. Effect of feeding thyroactive iodocasein on growth, feathering and weights of glands of young chicks. Poultry Sci. 22:374-380. Latimer, H. B., 1925. The relative postnatal growth of the systems and organs of the chicken. Anat. Record, 31:233-253. Latimer, H. B., 1932. Postnatal growth changes in the Single Comb White Leghorn chicken. Univ. Kansas Sci. Bull. 20(9): 199-206.
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Marsden, S. J., and J. H. Martin, 1955. Turkey Management, 6th Ed., The Interstate, Danville, Illinois. Naber, E. C , 1961. Utilization of poultry byproducts in feeds, 22-40. In Processing of poultry byproducts and their utilization in feeds. U.S.D.A. Utilization Research Report No. 3. Palsson, H., 1955. Conformation and body composition, 430-542. In Hammond, J. (editor) Progress in the Physiology of Farm Animals, Butterworths Scientific Publications, London.
Turner, C. W., M. R. Irwin and E. P. Reineke, 1944. Effect of feeding thyroactive iodocasein to Barred Rock cockerels. Poultry Sci. 23:242-246. Wheeler, R. S., E. Hoffmann and C. L. Graham, 1948. The value of thyroprotein in starting, growing and laying rations. 1. Growth, feathering and feed consumption of Rhode Island Red broilers. Poultry Sci. 27:103-111. Wyne, J. W., M. G. McCartney, R. D. Carter and V. D. Chamberlin, 1959. The effect of debeaking and wing clipping on growth and livability of turkey poults. Poultry Sci. 38:831-833.
Bone Darkening in Fryer Chickens as Related to Calcium and Phosphorus Levels in the Feed A N T H O N Y W. K O T U L A , J A M E S E . T H O M S O N AND J A M E S F . NOVOTNY
Market Quality Research Division, Agricultural Marketing Service, and E D M U N D H. M C N A L L Y
Animal Husbandry Research Division, Agricultural Research Service, United States Department of Agriculture, Beltsville, Maryland (Received for publication December 26, 1962)
T
fryer
it develops. Bone and meat discoloration
chickens is a fast growing enterprise
t h a t occurs during cooking of fryer chick-
in the poultry i n d u s t r y . T h e sooner the
ens which have been frozen m a y contrib-
actual
ute to the a p p a r e n t l y low consumer ac-
HE
or
associated
freezing
of
potential with
eviscerated
technical
freezing
problems
chickens
are
ceptability of these products.
solved, the better prepared the i n d u s t r y
Koonz (1946) indicated t h a t the mecha-
will be to meet the expanding d e m a n d , as
nism of darkening involves the leaching of
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Snedecor, G. W., 1956. Statistical Methods, 5th Ed., The Iowa State University Press, Ames, Iowa. Sturkie, P. D., 1954. Avian Physiology. Comstock Publishing Associates, Ithaca, N.Y. Titus, H. W., 1961. The Scientific Feeding of Chickens, 4th Ed., The Interstate, Danville, Illinois.